Veganism

[The Grand Nudger]

Gravity is a fact. The act of killing a person being moral or immoral is not a fact. When you walk off'n a cliff, you will fall down and hit the ground. When you kill someone, you may have committed a crime, or you may have defended yourself.

That's a good objectivist criticism...but ofc, it's not a good criticism if objectivism is false.  If subjectivism or relativism are true and you or your society say that killing a person is immoral that is..very much, the moral fact of the matter. Objective facts do not matter in any other moral schema, they are not the moral facts. The idea that defense modifies moral desert (or moral nature) is referring to a particular fact of the matter, not your opinion or your societies. It either was or wasn't self defense.

Similarly, when it comes to eating animals....that you have to eat, that you are a particular kind of creature on a particular kind of world, that you only have x y or z options available, that all of them are suboptimal....none of this matters outside of an objective understanding. The preists of the almighty chicken do not care about the details of your chicken eating offense. It's death no matter the facts of the matter. You should have committed self righteous suicide rather than eat the chicken, and since you didn't, they're going to correct that mistake.